New regulations in the United States and other countries require persons servicing air conditioner units and refrigeration units, such as refrigerators, freezers, and the like, to evacuate and recover the refrigerant (usually freon) which is removed from such systems without venting it to the atmosphere. This requirement is a substantial change from past practices, where freon and other refrigerants simply were vented to atmosphere during such repair or servicing operations.
These new regulations have resulted in the necessity for providing refrigerant recovery systems, which typically remove the refrigerant from the unit undergoing servicing, and supply that refrigerant, under pressure, to an approved storage tank. The storage tanks are similar to small portable propane gas tanks and the like, and are made to be carried by the service persons to and from the job site.
When the refrigerant is removed and supplied to the storage tank, it is quite hot. In some areas of the country, such as Arizona in the summertime, where the ambient temperature, particularly for roof air conditioners, can approach and exceed 115.degree. F., the efficiency of removal of refrigerant at such high temperatures is significantly impaired. As a consequence, it has been found necessary to cool the storage tank when it is being used to receive refrigerant removed from a system undergoing servicing. To accomplish this, some relatively complex refrigerant recovery systems have been developed. Three such systems are disclosed in the U.S. Pat. Nos. 4,761,961; to Marx Merritt 4,903,499; and Daily 5,101,637.
The Marx patent is directed to a refrigerant recovery system in which the recovery tank is cooled by a bath of liquid nitrogen in a Dewar Vessel 13. The requirement for the use of liquid nitrogen in this refrigerant recovery system results in an expensive, cumbersome apparatus.
The Daily U.S. Pat. No. 5,101,637 is directed to a refrigerant recovery system employing cryogenic cooling of the refrigerant container. The Daily system also uses liquid nitrogen to cool a jacket around the refrigerant container. The liquid nitrogen is vented to air, after the cooling function is completed by expansion of the nitrogen. The liquid nitrogen must be replenished; and it requires a separate tank in addition to the other components of the refrigerant recovery system.
The Merritt U.S. Pat. No. 4,903,499 also is directed to a relatively complex refrigerant recovery system. In Merritt, an annular jacket surrounds a special purpose storage bottle, which is provided with a valve-operated drain. Within the jacket, a puddle of refrigerant forms; and refrigerant is withdrawn from this puddle through a suction tube, and supplied to a low pressure suction line. The jacket functions to maintain the special recovery bottle at a low temperature to enhance the overall efficiency of the system. The non-standard recovery bottle, along with the specially constructed jacket, results in an expensive and cumbersome system.
Two patents, which are directed to beer keg coolers, are the U.S. Pat. Nos. 3,443,397 to Donovan and Justice 4,642,999. The Donovan patent is a double-walled device made of flexible material. A beer keg is placed in the container, and the spigot at the bottom of the keg extends through a sealed opening in the container bottom, to provide access to the keg. The inner portion of the container then is secured over the top of the keg; and the space between the inner and outer portions may be filled with ice. A lid is secured by means of a zipper, and handles are provided on the outer container to permit carrying of the ice-filled container and keg from one position to another.
The Justice patent discloses a foamed polystyrene cylindrical container, having a bottom portion and a cover. A keg of beer is placed in the bottom portion of the cooler. This portion forms a bucket; and ice is placed around the beer keg in the space between this lower bucket portion and the keg. The top of the Justice container then is fitted onto the bottom portion. This top has a circular opening in it for centering the outlet of the keg, which is placed in the container. Access to the keg then is obtained through the conventional keg outlet, which extends upwardly through the circular opening in the top of the container. The container top is not secured in any way to the bottom; and no handles for carrying the container with a keg inside are provided. If the keg is lifted, the container top simply is lifted off the bottom along with the keg. If the container is to be moved from place to place, it must be grasped from the bottom and carried. From the design of this container, it is apparent that it is not intended to be moved about from place to place, once it is filled.
It is desirable to provide an improved temperature control chamber for a refrigerant recovery system, which overcomes the disadvantages of the prior art noted above, is simple to use, low in cost, and which is readily portable.